This invention relates to an outside air system and combustion chamber closure assembly which provides means for supplying a sufficient amount of cooling air between the burning fuel and the combustion chamber closure assembly.
Fireplace closure assemblies are known, for example, U.S. Pat. Nos. 3,372,689, 3,870,032, 3,995,612 and 4,029,076. Outside air duct assemblies for fireplaces are also known, for example, U.S. Pat. Nos. 4,059,090, 4,061,127, 4,004,731 and 3,910,251. Many problems and disadvantages are encountered when utilizing an outside air duct assembly and a fireplace closure assembly, particularly when glass doors are used. Glass enclosures prevent sufficient amounts of air from entering the combustion chamber for the combustion of fuel and do not provide the necessary amounts of cooling air to prevent overheating of the fireplace and damage to or destruction of the glass panels.
Prefabricated fireplaces are designed and tested using fixed amounts of fuel input in accordance with the air flow through the frontal opening of the firebox or chamber. If flow of air is reduced by employing a glass enclosure system while maintaining the same fuel combustion rate, the fire chamber as well as the chimney temperatures will exceed the design capacity and may destroy or damage the glass enclosure assembly and may render the fireplace and chimney assembly unsafe.
Another disadvantage encountered when using a glass enclosure is the loss of radiant energy which would normally be radiated to the room as useful heat.
Fireplace designs which utilize an outside air system and a combustion chamber closure assembly provide combustion air either through the hearth or through one of the combustion chamber walls and may not be capable of providing sufficient amounts of air for fuel combustion as well as an excess of cooling air to prevent overheating of the fireplace with resultant damage to the closure assembly and fireplace itself.